Electric catalytic contact device



Aug. 18, 1959 s. B. WELCH ELECTRIC CATALYTIC CONTACT DEVICE Filed Sept 29 INVENTOR. STANLEY s. WELCH FIGI Hi5 ATTORNEY United States Patent ELECTRIC CATALYTIC CONTACT DEVICE Stanley B. Welch, Louisville, Ky., assignor to General Electric Company, a corporation of New York Application September 29, 1958, Serial No. 763,993

- 5 Claims. Cl. 219-38) The invention relates to catalytic fluid contact devices useful in promoting chemical reactions in a fluid stream, and more particularly to a device of this nature including catalytic material disposed so as to be contacted by a fluid stream and arranged to be heated by an electric heating element. l

The general object of this invention is to provide an improved catalytic fluid contact device of the electrically heated type so arranged that substantially all components of fluid passing through the device make at least one and frequently several contacts with heated catalytic material.

Further objects and advantages of the invention will become apparent as the following description proceeds, and the features of novelty which characterize the invention will be pointed out with particularity in the claims annexed to and forming a part of this specification.

Briefly stated, in accordance with one aspect of my invention, I provide an electric heating element and a screen member formed of or coated with catalytic material and arranged in a sinuous configuration so that the screen forms a sinuous passageway for the heating element. The screen and heating element are mounted in a closed housing provided with entrance and exit openings for the fluid to be treated, these openings being so located that fluid passing through the housing must either pass through a number of portions of the screen or along the sinuous passageway. In either case, substantially all components of the fluid come into contact at least once with the catalytic material before passing out of the housmg.

For a better understanding of this invention, reference may be made to the following description and the accompanying drawing in which:

Fig. l is a plan view of a preferred embodiment of my invention, some of the parts being broken away to show details of construction.

Fig. 2 is a cross-sectional view taken along the line 22 in Fig. 1.

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wall 9 by screen 15 (to be described below). It will of course be understood that the details of construction which have been described are illustrative only, and that various modifications in the manner in which the various walls of housing 1 are assembled may be made.

Mounted within housing 1 are an electric heating element 14 and screen means 15 formed of or coated with a catalytic material. Any suitable catalytic material may be utilized, depending upon the fluid to be treated and the reaction which is desired. Screens formed of platinum wire or platinum coated wire may of course be utilized. The device of the present invention has been found to be particularly useful when used in combination with an electric range oven for oxidizing the smoke and cooking odors produced during various cooking operations. In this application an oxidation catalyst is required and for this purpose screen 15 may be formed from steel wire resistant to high temperatures and coated with a film of a catalytic inorganic oxide such as catalytic alumina impregnated with a relatively small amount of a catalytic. metal such as platinum.

Both heating element 14 and catalytic screen 15 are formed in a sinuous configuration so as to provide an extended sinuous passageway between opening 6 in end wall 3 and openings 7 in end wall 4. In the illustrated embodiment of my invention, heating element 14 is of the sheathed type and is coiled in flat spiral form, being positioned so that the plane of the spiral form is generally parallel to end walls 3' and 4. Terminal portions 16 and 17 of the heating element are of course formed so as to project outside of housing 1.

Catalytic screen 15 is formed from an elongated strip of screen material and is interleaved with heating element Referring to the drawing, the numeral 1 designates a ,wall 4. In order to facilitate the mounting of housing 1 in a fluid duct or the like, a circular wall 8 and a cylindrical side wall 9 are provided so as to form a chamber overlying end wall 4. Wall 8 is preferably provided with an integral flange 10 defining an opening therein substantially in axial-alignment with and of the same size as opening 6 in end wall 3.

As shown in Fig. 2, walls 2 and 3 may be formed from a single piece of metal and provided with a flange 11 adapted to mate with and be attached to a flange 12 integral with walls 8 and 9. In this connection, the two flanges may be secured together by means of rivets 13 or other suitable fastening means. End wall 4 is preferably supported in position against the inset flange portion of 14 so as to define a spiral passageway for the heating element. Preferably screen 15 extends into abutting relation with walls 3 and 4 so as to form with these walls an enclosed passageway so arranged that fluid passing from opening 6 to opening 7 (or vice versa) must either pass through two or more portions of screen 15, or along the spiral passageway formed thereby.

In operation, it will be clear from the foregoing description that the housing assembly illustrated in the drawing may be connected in a fluid duct system so that the fluid passing therethrough must pass through compartment 5 in the manner described in the preceding paragraph. Heating element 14 is of course energized by means of suitable electrical connections (not shown) so as to heat screen 15 to its optimum reaction temperature, which will of course be dependent on the particular reaction to be effected.

While I have shown and described a particular embodiment of my invention, I do not desire the invention to be limited to the particular construction disclosed, and I intend by the appended claims to cover all modifications within the true spirit and scope of my invention.

What I claim is: i

1. A catalytic fluid contact device comprising a housing including side wall means and a pair of end walls forming a substantially closed compartment, an electric heating element of sinuous configuration in said housing, catalytic screen means in said housing, said screen means including screen portions positioned in generally parallel spaced relation to at least the major portion of said heating element, said screen portions being generally perpendicular to and in abutting relation with said end walls so as to provide a sinuous passageway for said heating clement, said housing having a first opening adjacent one end of said passageway and a second opening adjacent the other end thereof, whereby fluid passing through said openings and said housing necessarily contacts a large percentage of the surface of said screen means during its passage through said housing.

2. A catalytic fluid contact device comprising a housing including side wall means and a pair of end walls, an electric heating element disposed in generally flat spiral form within said housing, an elongated strip of catalytic screen material disposed in spiral form within said housing the plane of said material being generally perpendicular to the plane of the spiral form of said heating element, a plurality of turns of said heating element being located between adjacent turns of said screen material, said housing having a first opening adjacent one end of the open spiral passageway defined by said screen material and a second opening adjacent the other end thereof, whereby fluid passing through said openings and said housing necessarily contacts a large percentage of the surface of said screen material during its passage through said housing.

3. A catalytic fluid contact device comprising a housing including a continuous side wall and a pair of end walls, an elongated electric heating element coiled in flat spiral form in said housing, said heating element being positioned so that the plane of said spiral form is generally parallel to said end walls, a spiral catalytic screen interleaved with said heating element, said screen extending into abutting relation with said end walls so as to define a spiral passageway for said heating element, one of said end walls having a central opening therein overlying the innermost turn of said heating element, and the other of said end walls having at least one opening therein overlying a radially outermost portion of said passageway.

4. A catalytic fluid contact device comprising a housing including a cylindrical side wall and a pair of circular end walls, a sheathed electric heating element coiled in flat spiral form in said housing, said heating element being positioned so that the plane of said spiral form is generally parallel to said end walls, a spiral catalytic screen interleaved with said heating element, said screen extending into abutting relation with said end walls so as to define a spiral passageway for said heating element, one of said end walls having a central opening therein overlying the innermost turn of said heating element, and the other of said end walls having at least one opening therein overlying a radially outermost portion of said passageway.

5. A catalytic fluid contact device comprising a housing including a cylindrical side wall and a pair of mutually parallel circular end walls, a sheathed electric heating element coiled in flat spiral form in said housing, said heating element being positioned so that the plane of said spiral form is generally parallel to said end walls, a spiral catalytic screen interleaved with said heating element, said screen extending into abutting relation with said end walls so as to define a spiral pasageway for said heating element, one of said end walls having a central opening therein overlying the innermost turn of said heating element, the other of said end walls having a plurality of openings therein overlying the radially outermost portion of said pasageway, and wall means forming a chamber overlying said other end wall and in communication with said outermost portion of said passageway through said plurality of openings, said wall means having an opening therein substantially in axial alignment with and of the same size as said central opening.

References Cited in the file of this patent UNITED STATES PATENTS 

